Volcanic ash which has shut down airports across Europe and the United Kingdom is expected to linger in the atmosphere, worsening the financial impact on airlines around the world.

The hazardous ash cloud now extends from the Atlantic to the Russian capital and from the Arctic Circle to Austria.

Some experts predict it could continue swirling around the continent for months and with the airline industry and European economies still reeling from the global financial crisis, neither can afford a flight shutdown for that long.

No-one is quite sure when flights will return to normal.

That depends on when the volcano finishes spewing its hazardous ash into the sky and on the weather conditions.

Richard Arculus is a Professor of Geology at the Earth Sciences Research School at the Australian National University.

He says the volcano may continue erupting for weeks or months.

"It'll go round in whirls. As long as this ash is produced and as long as it's getting into the atmosphere, it'll be driven wherever the winds take it," he said.

"North-west Europe is successively hit with various kinds of weather fronts, so it might go away for a while, but as long as the ash is being produced, the next time the wind is heading towards the south and south-east from Iceland; it'll affect north-west Europe again."

There is still a chance this eruption could trigger other volcanoes in the area.

Dr Andrew Tupper is the line manager of the Volcanic Ash Advisory Centre in Darwin. He says the ash can stay in the atmosphere for a long time.

"Although it may not necessarily stay dangerous to aviation. It looks to me as though the main forecast is for a gradual eastward movement which is what we would normally expect," he said.

That could mean disruptions for flights in eastern Europe.

Economic impact

Meanwhile, Westpac bank's senior international economist Huw McKay was scheduled to fly to London on business yesterday afternoon.

He says even if the disruption to flights is short-lived, the financial impact on airlines will be significant.

"They're going to be dealing with accommodating these tourists who are stuck midway, whether that's in Singapore, whether that's in Dubai, whether that is somewhere in the US," he said.

"So, a lot of the costs of something like this sit with the airlines."

"Even within my own family, my sister's children are off in Rome on a school trip," he said.

"They cannot get back, so the knock on impact on the economy is actually going to be quite wide felt."

Mr Pope says countries like Greece and Spain, whose economies are already struggling, will feel the loss of the tourist dollar.

"It's really going to be Spain that would be the most effected, because a lot of people won't make the long haul to Greece until they can go for a two week stretch for their main summer holiday and we're just a couple of months away from when that season begins," he said.

"I think though you do get people who would make short quick flights down to Spain or Portugal, where they might have nearby holiday homes where they can go for a weekend and be back pretty easily on a Sunday evening.

"So there there's going to be a definite impact that is felt and will not serve those economies well at all."